P
US7999892B2ExpiredUtilityPatentIndex 96

Liquid crystal display device

Assignee: SEMICONDUCTOR ENERGY LABPriority: Dec 5, 2005Filed: Jan 21, 2011Granted: Aug 16, 2011
Est. expiryDec 5, 2025(expired)· nominal 20-yr term from priority
Inventors:KIMURA HAJIMEUOCHI HIDEKI
H10D 86/00G02F 1/133553G02F 1/134363G02F 1/133555G02F 2203/01G02F 1/134372G02F 2201/121G02F 1/136227G02F 1/133345G02F 2201/123G02F 1/133371G02F 1/136286G02F 1/134381G02F 1/134309G02F 1/1368
96
PatentIndex Score
28
Cited by
66
References
61
Claims

Abstract

It is an object of the present invention to provide a liquid crystal display device which has a wide viewing angle and less color-shift depending on an angle at which a display screen is seen and can display an image favorably recognized both outdoors in sunlight and dark indoors (or outdoors at night). The liquid crystal display device includes a first portion where display is performed by transmission of light and a second portion where display is performed by reflection of light. Further, a liquid crystal layer includes a liquid crystal molecule which rotates parallel to an electrode plane when a potential difference is generated between two electrodes of a liquid crystal element provided below the liquid crystal layer.

Claims

exact text as granted — not AI-modified
1. A liquid crystal display device comprising:
 a thin film transistor comprising: 
 a gate electrode; 
 a semiconductor layer comprising polycrystalline silicon; 
 a gate insulating layer separating the gate electrode and the semiconductor layer; 
 a first insulating layer over the thin film transistor; 
 a first conductive layer over the first insulating layer and in direct contact with the semiconductor layer through an opening in the first insulating layer; 
 a second insulating layer over the first conductive layer; 
 a common electrode over the second insulating layer; 
 a third insulating layer over the common electrode; and 
 a pixel electrode over the third insulating layer, 
 wherein the pixel electrode is in electrical contact with the first conductive layer through an opening in the third insulating layer and an opening in the second insulating layer; 
 wherein the common electrode is in electrical contact with a second conductive layer made from a same film as the first conductive layer; 
 wherein the second conductive layer is in electrical contact with a third conductive layer made of the same film as the gate electrode; and 
 wherein the common electrode substantially overlaps with the pixel electrode in an optically active region of a pixel. 
 
     
     
       2. A liquid crystal display device according to  claim 1 , wherein a region of the common electrode overlaps with the pixel electrode in the optically active region of the pixel, the region of the common electrode having a solid shape. 
     
     
       3. A liquid crystal display device according to  claim 1 ,
 wherein the common electrode comprises first conductive stripes; 
 wherein the pixel electrode comprises second conductive stripes; and 
 wherein the first conductive stripes and the second conductive stripes substantially do not overlap each other. 
 
     
     
       4. A liquid crystal display device according to  claim 1 , wherein the pixel electrode includes a first plurality of parallel and electrically conductive stripes making a first angle with a scan line and a second plurality of parallel and electrically conductive stripes making a second angle with the scan line. 
     
     
       5. A liquid crystal display device according to  claim 1 , wherein the pixel electrode includes slits. 
     
     
       6. A liquid crystal display device according to  claim 1 , wherein the pixel electrode is in electrical contact with the first conductive layer through a fourth conductive layer. 
     
     
       7. A liquid crystal display device according to  claim 1 , wherein the common electrode is a reflective electrode. 
     
     
       8. A liquid crystal display device according to  claim 1 , wherein the second conductive layer is in direct contact with the third conductive layer. 
     
     
       9. A liquid crystal display device according to  claim 1 , wherein the pixel electrode and the third conductive layer overlap each other in the pixel. 
     
     
       10. A liquid crystal display device according to  claim 1 , wherein the common electrode is in electrical contact with the second conductive layer through a fifth conductive layer. 
     
     
       11. A liquid crystal display device according to  claim 1 , wherein the gate electrode comprises molybdenum. 
     
     
       12. A liquid crystal display device according to  claim 1 , wherein the first conductive layer and the second conductive layer are made from a same film and have a multilayer structure comprising at least one of an aluminum layer and a titanium layer. 
     
     
       13. A liquid crystal display device according to  claim 1 , wherein the third insulating layer contains nitride. 
     
     
       14. A liquid crystal display device according to  claim 1 , wherein the second insulating layer includes an organic material. 
     
     
       15. An electronic appliance including a liquid crystal display device according to  claim 1 . 
     
     
       16. A liquid crystal display device comprising:
 a thin film transistor comprising: 
 a gate electrode; 
 a semiconductor layer comprising polycrystalline silicon; 
 a gate insulating layer separating the gate electrode and the semiconductor layer; 
 a first insulating layer over the thin film transistor; 
 a first conductive layer over the first insulating layer and in direct contact with the semiconductor layer through an opening in the first insulating layer; 
 a second insulating layer including an organic material over the first conductive layer; 
 a common electrode over the second insulating layer; 
 a third insulating layer containing nitride over the common electrode; and 
 a pixel electrode over the third insulating layer, 
 wherein the pixel electrode is in electrical contact with the first conductive layer through an opening in the third insulating layer and an opening in the second insulating layer; 
 wherein the common electrode is in electrical contact with a second conductive layer made from a same film as the first conductive layer; 
 wherein the second conductive layer is in electrical contact with a third conductive layer made of the same film as the gate electrode; and 
 wherein the common electrode substantially overlaps with the pixel electrode in an optically active region of a pixel. 
 
     
     
       17. A liquid crystal display device according to  claim 16 , wherein a region of the common electrode overlaps with the pixel electrode in the optically active region of the pixel, the region of the common electrode having a solid shape. 
     
     
       18. A liquid crystal display device according to  claim 16 ,
 wherein the common electrode comprises first conductive stripes; 
 wherein the pixel electrode comprises second conductive stripes; and 
 wherein the first conductive stripes and the second conductive stripes substantially do not overlap each other. 
 
     
     
       19. A liquid crystal display device according to  claim 16 , wherein the pixel electrode includes a first plurality of parallel and electrically conductive stripes making a first angle with a scan line and a second plurality of parallel and electrically conductive stripes making a second angle with the scan line. 
     
     
       20. A liquid crystal display device according to  claim 16 , wherein the pixel electrode includes slits. 
     
     
       21. A liquid crystal display device according to  claim 16 , wherein the pixel electrode is in electrical contact with the first conductive layer through a fourth conductive layer. 
     
     
       22. A liquid crystal display device according to  claim 16 , wherein the common electrode is a reflective electrode. 
     
     
       23. A liquid crystal display device according to  claim 16 , wherein the second conductive layer is in direct contact with the third conductive layer. 
     
     
       24. A liquid crystal display device according to  claim 16 , wherein the pixel electrode and the third conductive layer overlap each other in the pixel. 
     
     
       25. A liquid crystal display device according to  claim 16 , wherein the common electrode is in electrical contact with the second conductive layer through a fifth conductive layer. 
     
     
       26. A liquid crystal display device according to  claim 16 , wherein the gate electrode comprises molybdenum. 
     
     
       27. A liquid crystal display device according to  claim 16 , wherein the first conductive layer and the second conductive layer are made from a same film and have a multilayer structure comprising at least one of an aluminum layer and a titanium layer. 
     
     
       28. A liquid crystal display device according to  claim 16 , wherein the first insulating layer comprises nitride. 
     
     
       29. A liquid crystal display device according to  claim 16 , wherein the pixel electrode comprises indium tin oxide. 
     
     
       30. An electronic appliance including a liquid crystal display device according to  claim 16 . 
     
     
       31. A liquid crystal display device comprising:
 a thin film transistor comprising: 
 a gate electrode; 
 a semiconductor layer comprising polycrystalline silicon; 
 a gate insulating layer separating the gate electrode and the semiconductor layer; 
 a first insulating layer comprising nitride over the thin film transistor; 
 a first conductive layer over the first insulating layer and in direct contact with the semiconductor layer through an opening in the first insulating layer; 
 a second insulating layer over the first conductive layer; 
 a common electrode over the second insulating layer; 
 a third insulating layer over the common electrode; and 
 a pixel electrode over the third insulating layer, 
 wherein the pixel electrode is in electrical contact with the first conductive layer through an opening in the third insulating layer and an opening in the second insulating layer; 
 wherein the common electrode is in electrical contact with a second conductive layer made from a same film as the first conductive layer; 
 wherein the second conductive layer is in electrical contact with a third conductive layer made of the same film as the gate electrode; and 
 wherein the common electrode substantially overlaps with the pixel electrode in an optically active region of a pixel. 
 
     
     
       32. A liquid crystal display device according to  claim 31 , wherein a region of the common electrode overlaps with the pixel electrode in the optically active region of the pixel, the region of the common electrode having a solid shape. 
     
     
       33. A liquid crystal display device according to  claim 31 ,
 wherein the common electrode comprises first conductive stripes; 
 wherein the pixel electrode comprises second conductive stripes; and 
 wherein the first conductive stripes and the second conductive stripes substantially do not overlap each other. 
 
     
     
       34. A liquid crystal display device according to  claim 31 , wherein the pixel electrode includes a first plurality of parallel and electrically conductive stripes making a first angle with a scan line and a second plurality of parallel and electrically conductive stripes making a second angle with the scan line. 
     
     
       35. A liquid crystal display device according to  claim 31 , wherein the pixel electrode includes slits. 
     
     
       36. A liquid crystal display device according to  claim 31 , wherein the pixel electrode is in electrical contact with the first conductive layer through a fourth conductive layer. 
     
     
       37. A liquid crystal display device according to  claim 31 , wherein the common electrode is a reflective electrode. 
     
     
       38. A liquid crystal display device according to  claim 31 , wherein the second conductive layer is in direct contact with the third conductive layer. 
     
     
       39. A liquid crystal display device according to  claim 31 , wherein the pixel electrode and the third conductive layer overlap each other in the pixel. 
     
     
       40. A liquid crystal display device according to  claim 31 , wherein the common electrode is in electrical contact with the second conductive layer through a fifth conductive layer. 
     
     
       41. A liquid crystal display device according to  claim 31 , wherein the gate electrode comprises molybdenum. 
     
     
       42. A liquid crystal display device according to  claim 31 , wherein the first conductive layer and the second conductive layer are made from a same film and have a multilayer structure comprising at least one of an aluminum layer and a titanium layer. 
     
     
       43. A liquid crystal display device according to  claim 31 , wherein the third insulating layer contains nitride. 
     
     
       44. A liquid crystal display device according to  claim 31 , wherein the second insulating layer includes an organic material. 
     
     
       45. A liquid crystal display device according to  claim 31 , wherein the pixel electrode comprises indium tin oxide. 
     
     
       46. An electronic appliance including a liquid crystal display device according to  claim 31 . 
     
     
       47. A liquid crystal display device comprising:
 a thin film transistor comprising: 
 a gate electrode; 
 a semiconductor layer comprising polycrystalline silicon; 
 a gate insulating layer separating the gate electrode and the semiconductor layer; 
 a first insulating layer over the thin film transistor; 
 a first conductive layer over the first insulating layer and in direct contact with the semiconductor layer through an opening in the first insulating layer; 
 a second insulating layer over the first conductive layer; 
 a common electrode over the second insulating layer; 
 a third insulating layer over the common electrode; and 
 a pixel electrode comprising indium tin oxide over the third insulating layer, 
 wherein the pixel electrode is in electrical contact with the first conductive layer through an opening in the third insulating layer and an opening in the second insulating layer; 
 wherein the common electrode is in electrical contact with a second conductive layer made from a same film as the first conductive layer; 
 wherein the second conductive layer is in electrical contact with a third conductive layer made of the same film as the gate electrode; and 
 wherein the common electrode substantially overlaps with the pixel electrode in an optically active region of a pixel. 
 
     
     
       48. A liquid crystal display device according to  claim 47 , wherein a region of the common electrode overlaps with the pixel electrode in the optically active region of the pixel, the region of the common electrode having a solid shape. 
     
     
       49. A liquid crystal display device according to  claim 47 ,
 wherein the common electrode comprises first conductive stripes; 
 wherein the pixel electrode comprises second conductive stripes; and 
 wherein the first conductive stripes and the second conductive stripes substantially do not overlap each other. 
 
     
     
       50. A liquid crystal display device according to  claim 47 , wherein the pixel electrode includes a first plurality of parallel and electrically conductive stripes making a first angle with a scan line and a second plurality of parallel and electrically conductive stripes making a second angle with the scan line. 
     
     
       51. A liquid crystal display device according to  claim 47 , wherein the pixel electrode includes slits. 
     
     
       52. A liquid crystal display device according to  claim 47 , wherein the pixel electrode is in electrical contact with the first conductive layer through a fourth conductive layer. 
     
     
       53. A liquid crystal display device according to  claim 47 , wherein the common electrode is a reflective electrode. 
     
     
       54. A liquid crystal display device according to  claim 47 , wherein the second conductive layer is in direct contact with the third conductive layer. 
     
     
       55. A liquid crystal display device according to  claim 47 , wherein the pixel electrode and the third conductive layer overlap each other in the pixel. 
     
     
       56. A liquid crystal display device according to  claim 47 , wherein the common electrode is in electrical contact with the second conductive layer through a fifth conductive layer. 
     
     
       57. A liquid crystal display device according to  claim 47 , wherein the gate electrode comprises molybdenum. 
     
     
       58. A liquid crystal display device according to  claim 47 , wherein the first conductive layer and the second conductive layer are made from a same film and have a multilayer structure comprising at least one of an aluminum layer and a titanium layer. 
     
     
       59. A liquid crystal display device according to  claim 47 , wherein the third insulating layer contains nitride. 
     
     
       60. A liquid crystal display device according to  claim 47 , wherein the second insulating layer includes an organic material. 
     
     
       61. An electronic appliance including a liquid crystal display device according to  claim 47 .

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